topic Re: Omit observation for proc ttest in Statistical Procedures

Omit observation for proc ttest

toneill — Mon, 08 Dec 2014 19:43:05 GMT

Basic question for a new user:

I have a class variable (Y) that has >2 levels (yes/no/don't know/refused). I would like to perform a 2-sample t-test to compare population means on a survey at baseline (Z = 1). However, I know that my class variable will return an error of too many levels. How do I exclude "don't know" and "refused" observations (thus, only leaving those participants who responded "yes" or "no" responses)?

title X ;

proc ttest data = X ;

class Y ;

var A ;

where Z = 1 ;

run ;

Thank you.

Re: Omit observation for proc ttest

Haikuo — Mon, 08 Dec 2014 19:54:08 GMT

Something like this? Pay attention to the case for 'yes' , 'no'

title X ;

proc ttest data = X (where=(Y in ('yes', 'no')) ;

class Y ;

var A ;

where Z = 1 ;

run ;

Re: Omit observation for proc ttest

toneill — Mon, 08 Dec 2014 20:02:10 GMT

Thank you Hai.kuo

Just one minor correction on the parentheses:

title X ;

proc ttest data = X (where=(Y in ('yes','no'))) ;

class Y ;

var A ;

where Z = 1 ;

run ;

Works perfectly! Thanks for helping me learn another SAS trick!